JP2007084701A - Room temperature curing unsaturated resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a room temperature curing unsaturated resin composition which can be used for the VARTM method or VARI molding method, which excels particularly in low shrinkage, surface smoothness, water resistance and the like, and which has very high practicality because of being low in viscosity and a one-package type not causing separation, and to provide a molded product using it. <P>SOLUTION: The room temperature curing resin composition contains an unsaturated resin, a polymerizable unsaturated monomer and a shrink reducing agent. The unsaturated resin is an unsaturated polyester which uses dicyclopentadiene as a raw material, the polymerizable unsaturated monomer is styrene and its content in the composition is 40-60 mass%, and the shrink reducing agent comprises a styrene-acrylic random copolymer whose number average molecular weight is between 1,000 and <15,000. The molded product using the room temperature curing unsaturated resin composition is also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel and useful room temperature curable unsaturated resin composition. More specifically, the present invention contains an unsaturated polyester, a styrene acrylic copolymer, and a polymerizable unsaturated monomer. Mainly used in VARTM: Vacuum Assist Resin Transfer Molding (also referred to as VARI, Light-RTM), which is one of the room temperature curing closed molding methods for fiber reinforced radical curable plastics, especially excellent in low shrinkage and water resistance. The present invention relates to a room temperature curable unsaturated resin composition capable of giving a molded article having a good surface property.

The VARTM molding method has a feature that so-called capital investment such as a die cost and a press cost can be reduced because molding can be performed at room temperature and low pressure. Taking advantage of these characteristics, in recent years, the development of VARTM molding methods using low-shrinkable resins with excellent smoothness of the molded product surface is expected in the automobile and housing equipment fields, which aim for a high appearance on the molded product surface from the viewpoint of upgrading. ing.
However, conventional low-shrinkage resins are mainly those that exhibit a low shrinkage effect upon heat curing, and do not exhibit low shrinkage at room temperature curing, or have low water resistance even when room temperature curing is achieved (water absorption) (Patent document 1). Moreover, the resin composition which aims at low shrinkage by blending a filler cannot avoid an increase in viscosity, and has not been used in the VARTM molding method.
That is, in order to satisfy these various requirements, a room temperature curable unsaturated resin composition having a low viscosity and excellent in low shrinkage and water resistance is required.

Generally, a room temperature curable unsaturated resin using a polymerizable unsaturated monomer as a cross-linking agent causes problems such as strength reduction, cracking or warping due to a large volume shrinkage ratio of 5 to 12% at the time of curing. Or, the glass fiber is raised on the surface of the molded product, and as a result, a molded product having excellent surface smoothness cannot be obtained.
As a method of reducing these various problems, various thermoplastic polymers such as polystyrene, polyvinyl acetate, aliphatic saturated polyester, etc. are blended in a room temperature curable unsaturated resin as a low shrinkage agent, and constant A method of offsetting the curing shrinkage of the unsaturated polyester resin by using the thermal expansion of the thermoplastic resin by heating for a time is generally performed.

However, in the case of the room temperature curing VARTM molding method, when polyvinyl acetate is used as the low shrinkage agent, there is a problem that the water absorption rate of the molded product increases. In addition, when polystyrene, polymethyl methacrylate, and aliphatic saturated polyester are used as the low shrinkage agent, the resin composition may cause separation, and a low shrinkage effect is not exhibited in a room temperature curing system. There was a problem to say.
Japanese Patent Laid-Open No. 5-117346

  The subject of the present invention can be used for the VARTM method or the VARI molding method, and is particularly excellent in low shrinkage, surface smoothness, water resistance, etc., and has a low viscosity and does not separate in one liquid. The object is to provide a high room temperature curable unsaturated resin composition.

  Therefore, as a result of intensive studies to solve the above-mentioned problems, the present inventors have found that unsaturated polyester using dicyclopentadiene as a raw material, styrene acrylic random copolymer as a low shrinkage agent, and polymerizable unsaturated monomer. Unsaturated resin composition containing styrene as a body, VARTM molding is possible at room temperature, excellent surface smoothness of molded product, and also has sufficient water resistance, extremely useful room temperature curable unsaturated It discovered that it was a resin composition and came to complete this invention.

That is, the present invention is a room temperature curable unsaturated resin composition containing an unsaturated resin, a polymerizable unsaturated monomer, and a low shrinkage agent, wherein the unsaturated resin is an unsaturated resin made from dicyclopentadiene. It is a saturated polyester, the polymerizable unsaturated monomer is styrene, the content of the polymerizable unsaturated monomer in the resin composition is 40 to 60% by mass, and a styrene acrylic random copolymer as a low shrinkage agent. The present invention provides a room temperature curable unsaturated resin composition containing a polymer and having a number average molecular weight of 1,000 to less than 15,000.
Moreover, this invention provides the molded article characterized by using this normal temperature curable unsaturated resin composition.

  The room temperature curable unsaturated fat composition of the present invention expresses a low shrinkage effect at room temperature curing, and the molded product using this resin composition can improve surface smoothness, that is, improve the molding appearance. Water absorption can be improved. Moreover, since it is low-viscosity, the normal temperature low shrinkage which is the object of the present invention can be achieved without impairing moldability in FRP molding such as VARTM. Furthermore, it has the advantage that it is excellent in water resistance as compared with the prior art that is low-shrinkage at room temperature curing. Since the resin composition of the present invention has these advantages, it can be used as a resin material for molding various molded articles in various industrial fields including automobiles and housing fields.

  The unsaturated polyester using dicyclopentadiene as a raw material used in the present invention is one using dicyclopentadiene, unsaturated dibasic acid, glycol and, if necessary, a saturated dibasic acid as a raw material. Usually, it is obtained as a polymerizable unsaturated monomer solution having a resin solid content of 55 to 75% by mass.

  The unsaturated polyester using dicyclopentadiene as a raw material is manufactured by (1) a one-step synthesis method in which acid, glycol and dicyclopentadiene are simultaneously charged and condensed and simultaneously modified, and (2) the first step is anhydrous unsaturated. An acid and dicyclopentadiene are added in the presence of water and glycol to form a monoester, and then a second stage method in which glycol and acid are added in the second stage and a dehydration condensation reaction is performed is used. .

  Examples of the unsaturated acid which is a raw material of the unsaturated polyester using dicyclopentadiene as a raw material include unsaturated dibasic acids such as maleic acid / and anhydride, fumaric acid, itaconic acid / and anhydride, Orthophthalic acid / and anhydride, tetrahydrophthalic acid / and anhydride, hexahydrophthalic acid / and anhydride, isophthalic acid, terephthalic acid, adipic acid, succinic acid, malon as necessary for curing temperature, physical properties, etc. Saturated dibasic acids such as acid, glutaric acid, sebacic acid, 2,7-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid are used in combination so as not to lose the effects of the invention. Is also possible.

  Examples of the glycol include diethylene glycol, triethylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, neopentyl glycol, and 1,6-hexanediol. Ethylene glycol, propylene glycol, 1, 4-butanediol, hydrogenated bisphenol A, an adduct of bisphenol A and propylene oxide or ethylene oxide, 1,2-cyclohexane glycol, 1,3-cyclohexane glycol, 1,4-cyclohexane glycol, 1,4-cyclohexanedimethanol, Paraxylene glycol, bicyclohexyl-4,4′-diol, 2,6-decalin glycol, 2,7-decalin glycol and the like may be used in combination so as not to lose the effects of the invention.

  The dicyclopentadiene is contained in the unsaturated polyester in an amount of 1 to 55% by mass, preferably 25 to 50% by mass.

  In addition, the resin composition of the present invention may be used in combination with other radical-curable unsaturated resins for the purpose of controlling the physical properties, viscosity, moldability and the like of the molded product. The other radical curable unsaturated resin is a general unsaturated polyester resin other than the dicyclo unsaturated polyester resin, a vinyl ester resin, or a vinyl urethane resin. Within range is appropriate. In particular, the vinyl ester resin is desirably used in an amount of 5 to 15% by mass in the resin composition from the viewpoint of water resistance.

  As the other unsaturated polyester resin, the unsaturated polyester obtained by reacting an unsaturated dibasic acid or its anhydride with a saturated dibasic acid or a polyhydric alcohol is used as a polymerizable unsaturated monomer. It is obtained by dissolving in As the raw material, those described above are generally used. The vinyl ester resin includes a polycondensate of bisphenol and epichlorohydrin, a resin obtained by halogenating the same, a resin obtained by reacting epichlorohydrin with a polyhydric alcohol, dimer acid, trimer acid, novolac, etc., and an epoxy group. To an epoxy resin having two or more kinds of epoxy groups selected from cyclic epoxy resins, acrylic acid, methacrylic acid, cinnamic acid, crotonic acid, sorbic acid, monomethyl maleate, monopropyl maleate, monobutyl maleate, It is obtained by reacting one or more unsaturated monobasic acids selected from mono (2-ethylhexyl) maleate and the like, and is used in one or more types.

  Preferred vinyl ester resins are those obtained from bisphenol-type epoxy resins and unsaturated monobasic acids, such as di (meth) acrylates of bisphenol A-type epoxy resins, di-types of hydrogenated bisphenol A-type epoxy resins. (Meth) acrylate, di (meth) acrylate of bisphenol A ethylene oxide addition type epoxy resin, di (meth) acrylate of bisphenol A propylene oxide addition type epoxy resin, di (meth) acrylate of bisphenol F type epoxy resin, phenol novolac, or It comprises at least one (meth) acrylate of an epoxy resin obtained by a reaction between cresol novolac and epichlorohydrin or methyl epichlorohydrin.

  In addition, reaction with the above-mentioned epoxy resin and unsaturated monobasic acid becomes like this. Preferably it is 60-140 degreeC, Most preferably, it is performed using the esterification catalyst in the temperature within the range which is 80-120 degreeC.

  The vinyl urethane resin is a so-called urethane (meth) acrylate, which is a urethane compound containing at least one (meth) acryloyl group in the molecule. Such a resin is obtained by reacting, for example, a polyisocyanate, a polyol such as polyether polyol, and a hydroxyl group-containing (meth) acrylic compound. Each of the resins has an equivalent ratio of isocyanate group to hydroxyl group of approximately 1. It is obtained by reacting a compound. Specifically, a polyether polyol and a polyisocyanate are first reacted to obtain an isocyanate group-containing urethane prepolymer, and then obtained by reacting the prepolymer with a hydroxyl group-containing (meth) acrylic compound. .

  Polyol components constituting urethane (meth) acrylate include polyether polyols such as polypropylene oxide, polytetramethylene glycol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, polybutadiene diol, polyisoprene diol, polyester ether polyol, A polyester polyol etc. are mentioned.

  The polyisocyanate component constituting urethane (meth) acrylate includes 2,4-tolylene diisocyanate and its isomers or a mixture of isomers (hereinafter abbreviated as TDI), diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate. , Hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, tolidine diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, etc., and commercially available products are Bernock D-750, Crisbon NX (Dainippon Ink Chemical Co., Ltd. product), Death Module L (Sumitomo Bayer product), Coronate L (Nippon Polyurethane product), Takenate D102 (Takeda Pharmaceutical product), Iso Over preparative 143L (manufactured by Mitsubishi Chemical Corporation) can be exemplified, and can be used in their singly or two or more. Of the above polyisocyanates, diisocyanates, particularly TDI, are preferably used.

  As the polymerizable unsaturated monomer used in the present invention, styrene is used in an amount of 40 to 60% by mass in the resin composition. Typical examples that can be used in combination are t-butylstyrene and vinyltoluene. Or various styrenic monomers such as divinylbenzene; methyl methacrylate, butyl methacrylate, methacrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxypropyl, lauryl methacrylate, acrylic acid-β-hydroxyethyl or acrylic Various (meth) acrylates such as ethyl acid; ethylene glycol, polyethylene glycol, polypropylene glycol, 1,4-butanediol, 1,6 hexanediol, neopentyl glycol, trimethylolpropane, pentaerythritol or tris (β-hydroxy) ethyl Such as isocyanurate, polyhydric alcohols various; (meth) esters of acrylic acid: Alternatively, vinyl acetate, triallyl diallyl phthalate or isocyanuric acid.

  In particular, it is desirable to use styrene which has an excellent balance of low viscosity and low shrinkage. However, in the present invention, polymerizable unsaturated monomers other than those listed above do not preclude combined use within a range that does not depart from the purpose of the present invention or impair the effects of the present invention. .

  As the usage-amount of the said polymerizable unsaturated monomer used in this invention, it is 40-60 mass% in the normal temperature curable unsaturated resin composition containing the low shrinkage agent of this invention, Preferably it is 45-55. The range of mass% is appropriate. When it is less than 40% by mass, the low shrinkage effect is insufficient, the viscosity of the resin composition is high, and the workability is remarkably deteriorated. On the other hand, when it exceeds 60 mass%, it is unpreferable on a physical property. The viscosity of the room temperature curable unsaturated resin composition containing the low shrinkage agent of the present invention is preferably 50 to 500 mPa · s, more preferably 50 to 300 mPa · s. In each case, outside the lower and upper limit ranges is not preferable because in any case, molding becomes difficult.

The styrene acrylic random copolymer used in the present invention has a number average molecular weight of 1000 to less than 15000, preferably a weight average molecular weight of 3000 to 30000. If it is larger than this range, the viscosity of the room temperature curable unsaturated resin composition itself is increased, which is not preferable for maintaining fluidity and moldability. Moreover, when smaller than this range, it is unpreferable on the physical property of normal temperature curable unsaturated resin composition. Further, the content of the styrene acrylic random copolymer is preferably 3 to 20% by mass, particularly preferably 5 to 15% by mass, based on the total amount of the unsaturated resin and the polymerizable unsaturated monomer.
As raw materials constituting the styrene acrylic random copolymer used in the present invention, styrene monomers such as styrene monomer, α-methylstyrene, t-butylstyrene, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β -Various (meth) such as hydroxypropyl acrylate or β-hydroxypropyl methacrylate, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate or 2-ethylhexyl acrylate (Meth) acrylic acid ester monomers of acrylic acid and monohydric alcohols are used.
As a method for synthesizing the styrene acrylic random copolymer used in the present invention, the styrene monomer is preferably 50 to 5% by mass, particularly preferably 40 to 10% by mass, (meth) acrylic acid ester monomer 50 to 95% by mass, A polymerization method in which a compounding raw material consisting of 60 to 90% by mass is added by adding a polymerization initiator to the monomer or monomer without using a solvent or dispersion medium called bulk polymerization, bulk polymerization or bulk polymerization. Is obtained. Alternatively, a polymerization method in which a monomer and its polymer called suspension polymerization, suspension polymerization, and pearl polymerization are mechanically dispersed in an insoluble medium in a similar formulation, or a simple method called solution polymerization in a similar formulation. A polymerization method in which a monomer and a polymer are dissolved in a solvent is employed.
As initiators used in these polymerizations, peroxides, azo, azide compounds, and disulfides are used. A typical example of the peroxide is benzoyl peroxide. A typical azo and azide compound is azobisisobutyronitrile. A typical disulfide is tetramethylthiuram disulfide.
As a commercial item of the styrene acrylic random copolymer used for this invention, Dainippon Ink Chemical Industries make: Fine Dick series, Toa Gosei Co., Ltd. product: ARUFON UH series is mentioned.

If necessary, the room temperature curable unsaturated resin composition of the present invention may further include a filler, a colorant, a reinforcing material, a curing catalyst, a curing accelerator, a curing retarder, or an internal release agent that does not impair the moldability and viscosity. Of course, a mold agent or the like may be added.
Among them, as the coloring agent, first, conventionally known organic and inorganic dyes and pigments can be used, but in particular, they are excellent in heat resistance and transparency, and are also curable at room temperature. It is desirable to use a resin that does not significantly inhibit the curability of the unsaturated resin composition.

Examples of the reinforcing material used in the present invention generally include glass fibers such as a roving cloth mat, a chopped strand mat, a multi mat (manufactured by Saint-Gobain Vetrotex), and robicore (manufactured by Chomarat). In addition, various organic fibers such as vinylon, polyester, phenol, polyvinyl acetate, polyamide or polyphenylene sulfide; and various inorganic fibers such as carbon fiber, metal fiber or ceramic fiber, etc. It is also possible to use together. The shape of the reinforcing material is usually a knitted fabric or a non-woven fabric.
Further, the reinforcing material is not limited to fibers, but various plastic foams such as polyurethane foam, phenol foam, vinyl chloride foam or polyethylene foam; various hollow materials such as glass or ceramic. Cured bodies: various solids such as metals, ceramics, plastics, concrete, woods, and papers, molded products, and honeycomb structures.

  Of course, publicly known ones can be used as the filler described above, and among them, calcium carbonate powder, clay, alumina powder, magnet powder, talc, barium sulfate, silica powder, Examples thereof include glass powder, glass beads, mica, aluminum hydroxide, cellulose yarn, dredged sand, river sand, cold water stone, marble waste or crushed stone.

In particular, calcium carbonate powder is preferably used as a filler for the purpose of low shrinkage.
In addition, as the above-described curing accelerator, a metal compound is usually added as necessary, and the metal compound is generally an unsaturated polyester resin, that is, polymerizable with unsaturated polyesters. Metal compounds used in a mixture with unsaturated monomers are used, and among them, particularly representative ones include cobalt naphthonate, cobalt octoate, acetylacetone cobalt, calium hexoate, zirconium. Munaftnate, zirconium acetylacetonate, vanadium naphthonate, vanadium octoate, vanadium acetylacetonate or lithium acetylacetonate.
In addition, these various metal compounds may be used in combination as appropriate. Further, as other accelerators, various accelerators such as amine-based compounds, phosphorus-containing compounds, β-diketones, etc. Of course, it may be used in combination with known accelerators as appropriate.

  The addition amount of the accelerator can be appropriately adjusted depending on the desired gelation time, but preferably, the amount is within the range of 0.0001 to 0.5 parts by mass based on the metal content (in terms of metal content). Is appropriate.

Further, typical examples of the curing catalyst described above include azo compounds such as azobisisobutyronitrile; t-butylperoxybenzoate, benzoyl peroxide, acetylacetone peroxide, acetoacetate peroxide, methyl ethyl ketone. Although various organic peroxides such as peroxide or dicumyl peroxide, the curing catalyst is within a range of 0.1 to 4 parts by weight, particularly 100 parts by weight of the composition of the present invention. It is preferable to use within the range of 0.3 to 3 parts by mass.
Preferably, various redox curing agents such as a combination of acetylacetone peroxide and cobalt naphthonate are used. Furthermore, if a typical thing is specifically illustrated as an above-mentioned hardening retarder, hydroquinone, methylhydroquinone, or t-butylcatechol etc. will be mentioned, However, The said cure retarder is with respect to 100 mass parts of this invention composition. Preferably, it is used within a range of 0.0001 to 0.1 parts by mass.

  Of course, examples of the internal mold release agent described above can include conventionally known ones, but among them, various representatives such as stearic acid or zinc stearate can be cited as typical examples. Fatty acid esters; or alkyl phosphate esters, etc., and the internal mold release agent is usually used at a ratio of 0.5 to 5 parts by mass with respect to 100 parts by mass of the composition of the present invention. be able to.

  The room temperature curable unsaturated resin composition of the present invention thus obtained can be used for use because of its low shrinkage, surface smoothness or heat resistance (or water resistance). Of course, it can be used for various molded products, but it is used for composite moldings with fiber reinforcements, especially for VARTM or VARI molding methods. It is effective for.

  The VARTM method or the VARI molding method using the room temperature curable unsaturated resin composition of the present invention is to apply a release agent to a lower mold such as metal or FRP, apply a gel coating agent, cure, and then apply a fiber reinforcing material. Place the upper mold, which is placed on the mold, and if necessary, apply and harden the gel coat as well as the lower mold, and usually remove the air in the mold from one to several outlets provided on the upper mold, while the resin of the present invention from the injection port Inject the composition. After injection, the molded product is obtained by leaving the mold at room temperature for several hours to one day and removing the mold.

  Next, the present invention will be described in more detail with reference examples, examples and comparative examples. In the following, “part” and “%” are all based on mass unless otherwise specified.

(Synthesis example 1) [Preparation example of unsaturated polyester (UPE-1)]
A 5-liter four-necked flask equipped with a thermometer, stirrer, inert gas inlet, and reflux condenser was charged with 425 parts of diethylene glycol, 304 parts of 1,2-propylene glycol, and 1569 parts of maleic anhydride. The temperature was raised to 150 ° C. in a nitrogen atmosphere. Thereafter, at 130-140 ° C., 317.5 parts of dicyclopentadiene was added and reacted for 30 minutes. Further, while maintaining 130-140 ° C., 317.5 parts of dicyclopentadiene was added and reacted for 1 hour. When the solid acid value reached 229, diethylene glycol: 374 parts and 1,2-propylene glycol: 274 parts were charged, heated to 205 ° C., and reacted for 2 hours. Thereafter, the temperature was lowered to 200 ° C., and when the acid value reached 24.9, the mixture was cooled to 190 ° C., 1411 parts of styrene monomer was added, the non-volatile content was 70% by mass, and the viscosity at 25 ° C. was 890 mPa · s. , 4704 parts of unsaturated polyester UPE-1 having an acid value of 24.9 were obtained. The gel time was adjusted to 15 minutes with toluhydroquinone.

(Synthesis example 2) [Preparation example of epoxy acrylate (EPA-1)]
Into a 5-liter four-necked flask equipped with a thermometer, stirrer, inert gas inlet, and reflux condenser, Epicron 830 (Dainippon Ink Chemical Co., Ltd. epoxy resin: reaction product of epichlorohydrin and bisphenol F: Epoxy equivalent 180, number average molecular weight 344) 2970 parts, methacrylic acid 1456 parts, 2,6-di-tert-butyl-4-methylphenol 1.55 parts, triethylamine 13.3 parts, 90 ° C. in nitrogen atmosphere The mixture was heated up to react for 2 hours. Next, the reaction was continued until the acid value was 3.3 at 105 ° C. and cooled to obtain a viscous epoxy acrylate (EPA-1).

(Synthesis Example 3) [Synthesis Example of Styrene / Acrylic Copolymer (LPA-1) as Low Shrinkage Agent]
Into a reactor equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet, 66.7 parts of xylene was added, and the air in the reactor was replaced with nitrogen and heated to reflux. From there, 20 parts of 2-hydroxyethyl methacrylate, 25 parts of styrene monomer, 10 parts of n-butyl acrylate, 45 parts of methyl methacrylate and 2 parts of azobisisobutyronitrile as a polymerization initiator. The resulting mixture is added over 4-6 hours, and further maintained under reflux for 1 hour, and then cooled to a temperature of 80-100 ° C. in the range of 0.5 to azobisisobutyronitrile. Part was added to complete the polymerization.
A solid styrene acrylic random copolymer LPA-1 was obtained by removing the solvent from the polymerization solution thus obtained. The number average molecular weight of the obtained LPA-1 was 7700, and the weight average molecular weight was 14,000.

  60% by mass of UPE-1 obtained in Synthesis Example 1, 8% by mass of LPA-1 obtained in Synthesis Example 3, and 31% by mass of styrene monomer (ratio shown in Table 1) are blended, and room temperature curing is achieved. An unsaturated resin composition was obtained. After the preparation of the gel coat resin layer described below, a molded product was manufactured and evaluated by the following “formation of fiber reinforced plastic layer / preparation of fiber reinforced plastic plate”, and the results are shown in Table 1.

(Measurement of specific gravity of radical curable resin composition)
The specific gravity of the obtained unsaturated resin composition was measured according to JIS-K-6901 5.1.2. This is shown in Tables 1-4.

(Measurement of viscosity of radical curable resin composition)
The viscosity of the resin composition was measured for the resin composition according to JIS-K-5.5.1.

(Creation of cast plate)
To 100 parts of the above room temperature curable resin composition, 0.8 part of 6% cobalt naphthenate, 0.2 part of dimethylaniline, 2 parts of acetylacetone peroxide (Kayaku Akzo (manufactured): Trigonox 40) are added, A cast plate was prepared in accordance with JIS-K-6919 5.2.3.

(Measurement of specific gravity of cast plate)
The cast plate was cut out (50 × 50 mm), and the specific gravity of the cast plate was measured according to JIS-K-7112 6.1.4.

(Measurement of volumetric shrinkage of cast plate)
The casting plate was measured for volumetric shrinkage based on JIS-K-6901 Annex 3 (normative) volumetric shrinkage. If the volume shrinkage is 3% or less, it is considered that the resin composition exhibits a low shrinkage effect.

(Measurement of water absorption rate of casting plate)
The water absorption rate of the cast plate was measured based on the plastic water absorption test method of JIS-K-7209. The water absorption is considered to be excellent in water resistance at 0 to 1%.

(Creation of gel coat resin layer)
On a glass plate (350 × 350 mm) subjected to mold release treatment, gel coat resin POLYLITE GC-230 (manufactured by Dainippon Ink and Chemicals): 100 parts of pigment POLYTON WHITE 107J (manufactured by Dainippon Ink and Chemicals) : 10 parts, 0.5% of 6% cobalt naphthenate, hardener Parmec N (manufactured by NOF Corporation): 1.0 part of the gel coat resin composition blended with Iwata Painter Co., Ltd. spray gun W At -77 (φ2.5 mm), the film was sprayed to a thickness of 0.4 mm and cured at room temperature until tack-free.

(Formation of fiber reinforced plastic layer / preparation of fiber reinforced plastic plate)
NSG Vetrotex Co., Ltd. S600 / G500 / S600 is laid on the gel coat surface as a glass fiber reinforcement, a peel tube is placed 2 cm outside the glass fiber reinforcement, and a new glass plate is placed on it. A 3 mm thick mold was made. Resin composition having the composition shown in Example 1 in Table 1: 100 parts with respect to 0.8 parts of 6% cobalt naphthenate, 0.2 parts of dimethylaniline, acetylacetone peroxide (manufactured by Kayaku Akzo Co., Ltd.): Trigonox 40): 2 parts were blended and injected into a mold to perform FRP lamination molding. After curing at room temperature for 24 hours, demolding was performed to obtain a gel coat and fiber-reinforced plastic molded plate.

(Evaluation of fiber reinforced plastic molded product-surface smoothness evaluation)
The obtained fiber-coated plastic-coated plate with gel coat was observed for one month immediately after demolding using WaveScanPlus manufactured by BYK-Gardner, and the surface smoothness after 288 hours (12 days) was measured. It was described in. As an evaluation result, a GM-Tension value * calculated as a surface smoothness index by WaveScanPlus manufactured by BYK-Gardner was used. * The greater the GM-Tension (max 21), the better the surface smoothness. The evaluation results are shown in Table 1 with GM-Tension values of 10 or more being good and 10 or less being bad.

  Except for changing the ratio of unsaturated polyester UPE-1, styrene / acrylic copolymer LPA-1 and styrene, the same composition and evaluation were performed as in Example 1, and the results are shown in Table 1 together with the results.

  Except for changing the ratio of unsaturated polyester UPE-1, styrene / acrylic copolymer LPA-1 and styrene, the same composition and evaluation were performed as in Example 1, and the results are shown in Table 1 together with the results.

  Except for changing the proportion of unsaturated polyester UPE-1, styrene / acrylic copolymer LPA-1, and styrene, the same composition and evaluation were performed as in Example 1, and the results are shown in Table 2 together with the results.

  Unsaturated polyester UPE-1, styrene / acryl copolymer LPA-1, and styrene, together with epoxy acrylate resin EPA-1 blended at the blending ratio shown in Table 2, blended and evaluated in the same manner as in Example 1, and the results The results are shown in Table 2.

  Unsaturated polyester UPE-1, styrene-acrylic copolymer LPA-1, epoxy acrylate resin EPA-1, and the ratio of styrene were mixed and evaluated in the same manner as in Example 5 and shown in Table 2 together with the results. .

<Comparative Example 1>
Unsaturated polyester UPE-1 and styrene were blended in the proportions shown in Table 3, evaluated in the same manner as in Example 1, and shown in Table 3 together with the results.

<Comparative example 2>
Unsaturated polyester UPE-1, succinol SN-04D (manufactured by Denki Kagaku Kogyo Co., Ltd., vinyl acetate), and styrene were blended in the proportions shown in Table 3, and were evaluated in the same manner as in Example 1. It was shown in 3.

<Comparative Example 3>
Unsaturated polyester UPE-1, Dick styrene CR-3500 (manufactured by Dainippon Ink & Chemicals, Inc., polystyrene, number average molecular weight: 6000, solid) and styrene were blended in the proportions shown in Table 3, and Example 1 Evaluation was performed in the same manner, and the results are shown in Table 3.

<Comparative example 4>
Unsaturated polyester UPE-1, Dainal BR-84 (Mitsubishi Rayon Co., Ltd., polymethyl methacrylate, number average molecular weight: 26000, weight average molecular weight: 98000), and styrene were blended in the proportions shown in Table 4. Evaluation was carried out in the same manner as in Example 1, and the results are shown in Table 4.

<Comparative Example 5>
Unsaturated polyester UPE-1, styrene acrylic copolymer LPA-1, and styrene were blended in the proportions shown in Table 4 and evaluated in the same manner as in Example 1. The results are shown in Table 4.

<Comparative Example 6>
Unsaturated polyester UPE-1, Modiper (Nippon Yushi Co., Ltd. low shrinkage agent, product number: S-101-30, styrene solution with a resin content of 30% by mass), and styrene were blended in the proportions shown in Table 4, Evaluation was performed in the same manner as in Example 1, and the results are shown in Table 4.

  From Tables 1 to 4, Comparative Examples 1 to 6 were inferior in shrinkage or water resistance, but Examples 1 to 6 of the present invention were low in shrinkage and excellent in water resistance. It became clear.

The present invention can be used in the field of molding technology such as the VARTM method.

Claims (4)

A room temperature curable unsaturated resin composition containing an unsaturated resin, a polymerizable unsaturated monomer and a low shrinkage agent,
The unsaturated resin is an unsaturated polyester derived from dicyclopentadiene, the polymerizable unsaturated monomer is styrene, and the content of the polymerizable unsaturated monomer in the resin composition is 40 to 60 mass. %, A styrene-acrylic random copolymer as a low shrinkage agent, and having a number average molecular weight of 1,000 to less than 15,000.   The room temperature curable unsaturated resin composition according to claim 1, wherein the styrene acrylic random copolymer has a weight average molecular weight of 3000 to 30000.   The room temperature curable unsaturated according to claim 1 or 2, wherein the content of the styrene acrylic random copolymer is 5 to 15% by mass with respect to the total amount of the unsaturated resin and the polymerizable unsaturated monomer. Resin composition. A molded product comprising the room temperature curable unsaturated resin composition according to claim 1.